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Duplicate each element of a vector.
for an n-dimensional vector x, the function should return another vector 2n-dimension which each element is repeated twice. Ex...

11 years ago

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Project Euler: Problem 10, Sum of Primes
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below the input, N. Thank you <http:/...

11 years ago

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Prime factor digits
Consider the following number system. Calculate the prime factorization for each number n, then represent the prime factors in a...

11 years ago

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How long is the longest prime diagonal?
Stanislaw Ulam once observed that if the counting numbers are <http://en.wikipedia.org/wiki/Ulam_spiral arranged in a spiral>, t...

11 years ago

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Find a subset that divides the vector into equal halves
Given a vector x, return the indices to elements that will sum to exactly half of the sum of all elements. Example: Inpu...

11 years ago

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Find perfect placement of non-rotating dominoes (easier)
Given a list of ordered pairs, find the order they should be placed in a line, such that the sum of the absolute values of the d...

11 years ago

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Stuff the Board
You have a stack of tiles to put onto an array-like playing board. Each tile has a number (always an integer), and the board var...

11 years ago

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Find the biggest empty box
You are given a matrix that contains only ones and zeros. Think of the ones as columns in an otherwise empty floor plan. You wan...

11 years ago

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Spot the outlier
All points except for one lie on a line. Which one is the outlier? Example: You are given a list of x-y pairs in a column ...

11 years ago

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Solitaire Cipher
Implement the <http://en.wikipedia.org/wiki/Solitaire_(cipher) solitaire cipher>. Since this is from Wikipedia, I am capturin...

11 years ago

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Find a Pythagorean triple
Given four different positive numbers, a, b, c and d, provided in increasing order: a < b < c < d, find if any three of them com...

11 years ago

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Triangle sequence
A sequence of triangles is constructed in the following way: 1) the first triangle is Pythagoras' 3-4-5 triangle 2) the s...

11 years ago

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Mandelbrot Numbers
The <http://en.wikipedia.org/wiki/Mandelbrot_set Mandelbrot Set> is built around a simple iterative equation. z(1) = c z...

11 years ago

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Return 'on' or 'off'
When the input is true, return 'on', otherwise, return 'off'.

11 years ago

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Is A the inverse of B?
Given a matrix A and a matrix B, is A the inverse of B? >>A=[2,4;3,5]; >>B=[-2.5,2;1.5,-1]; >>isInverse...

11 years ago

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Find the palindrome
Given the string a, find the longest palindromic sub-string b. So when a = 'xkayakyy'; you should return b = 'kayak';

11 years ago

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Back to basics 26 - Keywords
Covering some basic topics I haven't seen elsewhere on Cody. Return a cell array of strings of all MATLAB keywords.

11 years ago

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Back to basics 23 - Triangular matrix
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, return a matrix with all elements above a...

11 years ago

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Back to basics 25 - Valid variable names
Covering some basic topics I haven't seen elsewhere on Cody. Given a string, return true if it is a valid MATLAB variable nam...

11 years ago

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Back to basics 4 - Search Path
Covering some basic topics I haven't seen elsewhere on Cody. Return a string that is the user's portion of the current search...

11 years ago

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Replace May with April
For instance, if the input is input_str = 'The flowers may bloom in April'; then the output is output_str = 'The flo...

11 years ago

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Make a 1 hot vector
Make a vector of length _N_ that consists of all zeros except at index _k_, where it has the value 1. Example: Input ...

11 years ago

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Back to basics 15 - classes
Covering some basic topics I haven't seen elsewhere on Cody. Return the class of the input variable.

11 years ago

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Say something funny
Say something funny, or not. Your solution will be (fully automatically and objectively) scored based on how clever or funny ...

11 years ago

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Find state names that end with the letter A
Given a list of US states, remove all the states that end with the letter A. Example: Input s1 = 'Alabama Montana Nebras...

11 years ago

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Who is the smartest MATLAB programmer?
Who is the smartest MATLAB programmer? Examples: Input x = 'Is it Obama?' Output = 'Me!' Input x = 'Who ?' Ou...

11 years ago

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give nth decimal place of pi
max 15th place after the decimal point is ok for now

11 years ago

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Side of a rhombus
If a rhombus has diagonals of length x and x+1, then what is the length of its side, y? <<http://upload.wikimedia.org/wikipe...

11 years ago

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Side of an equilateral triangle
If an equilateral triangle has area A, then what is the length of each of its sides, x? <<http://upload.wikimedia.org/wikipe...

11 years ago

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Flag largest magnitude swings as they occur
You have a phenomenon that produces strictly positive or negative results. delta = [1 -3 4 2 -1 6 -2 -7]; Marching thr...

11 years ago